1.Guideline for Adult Weight Management in China
Weiqing WANG ; Qin WAN ; Jianhua MA ; Guang WANG ; Yufan WANG ; Guixia WANG ; Yongquan SHI ; Tingjun YE ; Xiaoguang SHI ; Jian KUANG ; Bo FENG ; Xiuyan FENG ; Guang NING ; Yiming MU ; Hongyu KUANG ; Xiaoping XING ; Chunli PIAO ; Xingbo CHENG ; Zhifeng CHENG ; Yufang BI ; Yan BI ; Wenshan LYU ; Dalong ZHU ; Cuiyan ZHU ; Wei ZHU ; Fei HUA ; Fei XIANG ; Shuang YAN ; Zilin SUN ; Yadong SUN ; Liqin SUN ; Luying SUN ; Li YAN ; Yanbing LI ; Hong LI ; Shu LI ; Ling LI ; Yiming LI ; Chenzhong LI ; Hua YANG ; Jinkui YANG ; Ling YANG ; Ying YANG ; Tao YANG ; Xiao YANG ; Xinhua XIAO ; Dan WU ; Jinsong KUANG ; Lanjie HE ; Wei GU ; Jie SHEN ; Yongfeng SONG ; Qiao ZHANG ; Hong ZHANG ; Yuwei ZHANG ; Junqing ZHANG ; Xianfeng ZHANG ; Miao ZHANG ; Yifei ZHANG ; Yingli LU ; Hong CHEN ; Li CHEN ; Bing CHEN ; Shihong CHEN ; Guiyan CHEN ; Haibing CHEN ; Lei CHEN ; Yanyan CHEN ; Genben CHEN ; Yikun ZHOU ; Xianghai ZHOU ; Qiang ZHOU ; Jiaqiang ZHOU ; Hongting ZHENG ; Zhongyan SHAN ; Jiajun ZHAO ; Dong ZHAO ; Ji HU ; Jiang HU ; Xinguo HOU ; Bimin SHI ; Tianpei HONG ; Mingxia YUAN ; Weibo XIA ; Xuejiang GU ; Yong XU ; Shuguang PANG ; Tianshu GAO ; Zuhua GAO ; Xiaohui GUO ; Hongyi CAO ; Mingfeng CAO ; Xiaopei CAO ; Jing MA ; Bin LU ; Zhen LIANG ; Jun LIANG ; Min LONG ; Yongde PENG ; Jin LU ; Hongyun LU ; Yan LU ; Chunping ZENG ; Binhong WEN ; Xueyong LOU ; Qingbo GUAN ; Lin LIAO ; Xin LIAO ; Ping XIONG ; Yaoming XUE
Chinese Journal of Endocrinology and Metabolism 2025;41(11):891-907
Body weight abnormalities, including overweight, obesity, and underweight, have become a dual public health challenge in Chinese adults: overweight and obesity lead to a variety of chronic complications, while underweight increases the risks of malnutrition, sarcopenia, and organ dysfunction. To systematically address these issues, multidisciplinary experts in endocrinology, sports science, nutrition, and psychiatry from various regions have held multiple weight management seminars. Based on the latest epidemiological data and clinical evidence, they expanded the guideline to include assessment and intervention strategies for underweight, in addition to the core content of obesity management. This guideline outlines the etiological mechanisms, evaluation methods, and multidimensional management strategies for overweight and obesity, covering key areas such as diagnosis and assessment, medical nutrition therapy, exercise prescription, pharmacological intervention, and psychological support. It is intended to provide a scientific and standardized approach to weight management across the adult population, aiming to curb the rising prevalence of obesity, mitigate complications associated with abnormal body weight, and improve nutritional status and overall quality of life.
2.CT and MRI manifestations of gastritis cystica profunda
Qian YANG ; Jing YUAN ; Ruili MAO ; Zhiying XUE ; Peng ZHONG ; Weiguo ZHANG ; Chunhua LIU
Chinese Journal of Medical Imaging Technology 2025;41(2):277-280
Objective To observe CT and MRI manifestations of gastritis cystica profunda(GCP).Methods Seventeen patients with GCP confirmed by operation or biopsy pathology were enrolled,and lesions'CT and MRI manifestations were observed.Results Among 17 cases,16 cases(16/17,94.12%)were found with single lesion and 1(1/17,5.88%)with diffuse multiple lesions.The lesion located in the fundus of stomach in 5 cases(5/17,29.41%),in the body of stomach in 4 cases(4/17,23.53%),in the cardia and antrum of stomach each in 3 cases(3/17,17.65%)and in the pylorus in 1 case(1/17,5.88%),while 1 case(1/17,5.88%)was found with diffused multiple lesions within stomach.Non-enhance CT showed local thickening of gastric wall in 10 cases(10/17,58.82%),all were isodensities,and the mucosa uniformly enhanced in contrast enhance CT(CECT).Predominately cystic lesion in 5 cases(5/17,29.41%)presented as submucosal cystic protrusions,and grew into the stomach cavity with circular or oblong low density in non-enhanced CT,while sandwich enhancement of mucosa was observed in CECT.Among these 5 cases(5/17,29.41%),MRI showed lesion confined to the submucosa with low signal on T1WI and high signal on T2WI,while diffusion weighted imaging showed unrestricted diffusion,and the enhancement pattern was consistent with that of CT in 2 cases.In other 2 cases(2/17,11.77%)with cystic-solid lesion,non-enhanced CT showed soft tissue density,while CECT showed lump-like stratified enhancement.Conclusion CT and MRI manifestations of GCP had certain characteristics.
3.Sj?gren disease complicated by primary breast lymphoma:A case report
Yuan NING ; Xiaoying ZHANG ; Xue LI ; Yuan LI ; Jing HE ; Yuebo JIN
Journal of Peking University(Health Sciences) 2025;57(4):808-811
This case report describes the diagnostic and therapeutic management of a 67-year-old fe-male with a 40-year history of Sj?gren disease(SjD)who was hospitalized for evaluation of recurrent fever lasting over one month.The patient's initial diagnosis of SjD was established four decades earlier based on clinical manifestations,serological findings,and evidence of glandular damage.Her clinical presenta-tion included recurrent parotid gland enlargement accompanied by sicca symptoms,notably persistent xerostomia and xerophthalmia,followed by progressive dental caries.Serological studies demonstrated positivity for antinuclear antibodies,anti-SSA/Ro,and anti-α-fodrin antibodies.Objective assessments confirmed significant ocular involvement(Schirmer's test≤5 mm/5 min)and pulmonary interstitial changes on chest CT,consistent with the 2016 American College of Rheumatology and European League Against Rheumatism(ACR/EULAR)classification criteria for SjD.The patient's condition remained sta-ble under low-dose corticosteroids and disease-modifying anti-rheumatic drugs(DMARDs)until the re-cent onset of prolonged fever,necessitating evaluation for fever of unknown origin.Differential diagnoses considered disease flare,infection,and malignancy.The European Sj?gren's Syndrome Disease Activity Index(ESSDAI)score was 5 points,indicating moderate systemic disease activity.Initial laboratory in-vestigations revealed no evidence of infection,and empirical anti-infective therapy proved ineffective.No-tably,despite the absence of lymphadenopathy,laboratory findings including borderline positive IgM λ M-protein,elevated lactate dehydrogenase,hyperferritinemia,and increased β2-microglobulin levels raised suspicion for lymphoproliferative disorders,given the established association between SjD and lymphoma.Bone marrow aspiration showed no significant abnormalities,but PET/CT imaging detected hypermetabolic lesions in the left breast and right distal femur,suggesting potential malignancy.Subse-quent histopathological examination of the breast lesion confirmed non-Hodgkin's lymphoma(NHL),specifically diffuse large B-cell lymphoma(DLBCL)of the germinal center B-cell(GCB)subtype.Treatment with R-CHOP chemotherapy(rituximab,cyclophosphamide,doxorubicin,vincristine,and prednisone)induced complete metabolic remission after three cycles.However,she subsequently developed treatment-related complications,including myelosuppression and pulmonary infection.This case underscores the importance of maintaining a high index of suspicion for atypical site involvement in SjD patients,particularly when lymphoma risk factors are present.Comprehensive differential diagnosis should include lymphoma and other malignancies,and the diagnostic value of PET/CT and histopatholog-ical examination in disease evaluation is emphasized.SjD complicated by breast lymphoma is exceptional-ly rare,and its pathogenesis may involve lymphocytic infiltration,abnormal activation of lymphocytes,formation of ectopic germinal centers in the breast,and eventual malignant transformation.These mecha-nisms require further investigation through clinical and basic research studies.
4.CT and MRI manifestations of gastritis cystica profunda
Qian YANG ; Jing YUAN ; Ruili MAO ; Zhiying XUE ; Peng ZHONG ; Weiguo ZHANG ; Chunhua LIU
Chinese Journal of Medical Imaging Technology 2025;41(2):277-280
Objective To observe CT and MRI manifestations of gastritis cystica profunda(GCP).Methods Seventeen patients with GCP confirmed by operation or biopsy pathology were enrolled,and lesions'CT and MRI manifestations were observed.Results Among 17 cases,16 cases(16/17,94.12%)were found with single lesion and 1(1/17,5.88%)with diffuse multiple lesions.The lesion located in the fundus of stomach in 5 cases(5/17,29.41%),in the body of stomach in 4 cases(4/17,23.53%),in the cardia and antrum of stomach each in 3 cases(3/17,17.65%)and in the pylorus in 1 case(1/17,5.88%),while 1 case(1/17,5.88%)was found with diffused multiple lesions within stomach.Non-enhance CT showed local thickening of gastric wall in 10 cases(10/17,58.82%),all were isodensities,and the mucosa uniformly enhanced in contrast enhance CT(CECT).Predominately cystic lesion in 5 cases(5/17,29.41%)presented as submucosal cystic protrusions,and grew into the stomach cavity with circular or oblong low density in non-enhanced CT,while sandwich enhancement of mucosa was observed in CECT.Among these 5 cases(5/17,29.41%),MRI showed lesion confined to the submucosa with low signal on T1WI and high signal on T2WI,while diffusion weighted imaging showed unrestricted diffusion,and the enhancement pattern was consistent with that of CT in 2 cases.In other 2 cases(2/17,11.77%)with cystic-solid lesion,non-enhanced CT showed soft tissue density,while CECT showed lump-like stratified enhancement.Conclusion CT and MRI manifestations of GCP had certain characteristics.
5.Artificial intelligence and cervical spine image recognition:application prospects and challenges
Simin WANG ; Dezhou ZHANG ; Jing ZHAO ; Chaoqun WANG ; Kun LI ; Jie CHEN ; Xue BAI ; Hailong ZHAO ; Shaojie ZHANG ; Yuan MA ; Yunteng HAO ; Yang YANG ; Zhijun LI ; Jun SHI ; Xing WANG
Chinese Journal of Tissue Engineering Research 2025;29(33):7231-7240
BACKGROUND:Cervical spondylosis is a chronic degenerative disease that has become one of the most common and frequent diseases threatening human health.At present,the initial diagnosis of the cervical spine and its surrounding structures mainly relies on the interpretation of medical images by radiologists,which not only requires a high level of technical requirements for operators,but also has the disadvantages of strong subjectivity,high labor intensity,and low efficiency.With the rapid development of artificial intelligence technology,its powerful data processing and image recognition capabilities have shown broad application prospects in the medical field.Deep learning has also made certain progress in the research of spinal diseases.OBJECTIVE:To summarize the current status and research progress in the application of artificial intelligence technology in cervical spine imaging images in recent years,evaluating the performance of artificial intelligence models as well as future trends and challenges to be overcome.METHODS:The first author searched the relevant articles in WanFang,CNKI,and PubMed in June 2024.The Chinese search terms were"artificial intelligence,deep learning,cervical spine."English serach terms were"artificial intelligence,Al,cervical vertebrae,cervical."Finally,101 articles were included and analyzed.RESULTS AND CONCLUSION:(1)Artificial intelligence technology can realize automatic segmentation of cervical vertebrae and measurement of curvature change by segmentation,classification,landmarks recognition of medical image parts,detect cervical vertebral fracture,nerve root,and spinal cord type cervical spondylosis,identify cervical spine ossification of posterior longitudinal ligament,and predict post-surgery related risk factors and cervical vertebra maturation classification.(2)Although artificial intelligence technology has shown great potential in the field of cervical spine research,it is still in the early stages of exploration and rapid development,with unlimited room for development and innovation.
6.Preparation of doxorubicin-loaded polyphyllin H liposomes and synergistic anti-tumor activity against non-small cell lung cancer in vitro
Yining LIU ; Dawei ZHOU ; Shouchang GAI ; Lu SUI ; Xue SUN ; Zhenhua TONG ; Yuhang WANG ; Jing ZHAO ; Xiaofeng YUAN ; Yong XIANG
Journal of Army Medical University 2025;47(17):2134-2144,封3
Objective To prepare glucose transporter 1(Glut1)-targeted doxorubicin(DOX)-loaded liposomes(doxorubicin/polyphyllin H-liposomes,DOX/ppH-LPs)using polyphyllin H(ppH)instead of cholesterol as the liposomal membrane material,and to investigate their in vitro synergistic anti-tumor activity against non-small cell lung cancer(NSCLC).Methods DOX/ppH-LPs were prepared using thin-film hydration,and the formulation was optimized by single-factor investigation.The optimized DOX/ppH-LPs were characterized for morphology,particle size,polydispersity index(PDI),and zeta potential with transmission electron microscopy(TEM)and dynamic light scattering(DLS).Drug loading DL%was determined by high-performance liquid chromatography(HPLC).The storage stability was evaluated by observing in PBS at 4℃for 7 d,and the serum stability was observed in DMEM containing 10%fetal bovine serum(FBS)at 37℃for 48 h.In vitro drug release was studied in PBS at pH 7.4 and pH 5.0 values,respectively.Human NSCLC A549 cells were subjected as the model,MTT assay was performed to detect the proliferation inhibition by DOX/ppH-LPs at different concentrations(0.5,5.0,15.0 μg/mL)and the control group(ppH+DOX/LPs,a physical mixture of free ppH and DOX-loaded liposomes).Fluorescence microscopy was used to observe cellular uptake of DOX/ppH-LPs and DOX/LPs(containing 5 μg/mL DOX)at 15 min and 2 h.Live/dead cell staining was applied to assess apoptosis/necrosis induced by formulations(15 μg/mL DOX)after 48 h incubation.Transwell assay was conducted to evaluate inhibitory effect on cell migration and invasion,and the targeting property and in vitro synergistic anti-NSCLC activity of DOX/ppH-LPs were then comprehensively evaluated.Results The optimal formulation of DOX/ppH-LPs was determined as hydration temperature at 50℃,6 mg DOX,2 mg ppH,and 24 mg lecithin.The prepared DOX/ppH-LPs were in spherical shape,uniform distribution,and at an average particle size of 145.13±22.14 nm,a PDI of 0.15±0.05,a zeta potential of-23.92±1.73 mV,and a DL of 10.13±0.71%for DOX and(1.22±0.21)%for ppH.DOX/ppH-LPs maintained stable particle size,PDI,and exhibited significantly unchanged zeta potential after storage in PBS at 4℃for 7 d or incubation in DMEM containing 10%FBS at 37℃for 48 h,demonstrating excellent physical and serum stability.Both liposomes showed slow release at pH 7.4 value,while drug release was significantly accelerated at pH 5.0 value(P<0.05),indicating pH-sensitive release characteristics.MTT assay revealed that DOX/ppH-LPs exerted significantly stronger cytotoxicity against A549 cells than the ppH+DOX/LPs control group(P<0.05).Compared with ppH+DOX/LPs,DOX/ppH-LPs showed remarkably enhanced cellular uptake in A549 cells(P<0.05),with more DOX localized in the nucleus.Live/dead cell staining showed that at the same DOX concentration(15 μg/mL),the proportion of apoptotic/necrotic cells induced by DOX/ppH-LPs was significantly higher than that of the DOX/LPs control group.Transwell assay demonstrated that there were significantly less cells migrating and invading through the membrane in the DOX/ppH-LPs group than the ppH+DOX/LPs group.Conclusion Glut1-targeted doxorubicin-loaded liposomes(DOX/ppH-LPs)constructed by substituting cholesterol with ppH can target NSCLC cells,significantly enhance the in vitro synergistic anti-NSCLC activity of DOX and ppH.
7.AuNPs-FeCDs Dual Nanozyme Cascade System Integrated with A Smartphone Platform for Sensitive Detection of Glucose
Qing-Jing YE ; Xue-Ying ZHOU ; Yan-Ying ZHENG ; Yun ZHANG ; Wen-Ying JIN ; Ya-Li YUAN
Chinese Journal of Analytical Chemistry 2025;53(9):1457-1466
A centrifugation-free,single-reaction colorimetric method for detection of glucose,utilizing a dual nanozyme cascade system based on gold nanoparticles(AuNPs)and iron-doped carbon dots(FeCDs),was developed in this work.The AuNPs exhibited glucose oxidase-like activity to catalyze glucose oxidation for generation of H2O2,while the FeCDs demonstrated peroxidase-like activity to subsequently catalyze the H2O2-mediated oxidation of 3,3',5,5'-tetramethylbenzidine(TMB).To prevent interference from the blue signal generated by self-aggregation of AuNPs in subsequent quantitative detection,the reaction system was terminated with HCl,converting oxTMB into a stable yellow product.Based on changes in the absorbance at 450 nm of this yellow solution,a quantitative relationship was established between glucose concentration and absorbance at 450 nm(A450).Experimental results demonstrated that this sensor achieved a linear detection range of 44 μmol/L to 11.11 mmol/L(R2=0.993)with a detection limit of 30.68 μmol/L and spiked recoveries of 97.9%-104.7%.By integrating smartphone-based color recognition capabilities,a rapid visual detection platform was established for quantification of glucose through RGB analysis.The validation experimental results using commercial glucose injection samples further confirmed the practical application potential of this methodology.
8.Guideline for Adult Weight Management in China
Weiqing WANG ; Qin WAN ; Jianhua MA ; Guang WANG ; Yufan WANG ; Guixia WANG ; Yongquan SHI ; Tingjun YE ; Xiaoguang SHI ; Jian KUANG ; Bo FENG ; Xiuyan FENG ; Guang NING ; Yiming MU ; Hongyu KUANG ; Xiaoping XING ; Chunli PIAO ; Xingbo CHENG ; Zhifeng CHENG ; Yufang BI ; Yan BI ; Wenshan LYU ; Dalong ZHU ; Cuiyan ZHU ; Wei ZHU ; Fei HUA ; Fei XIANG ; Shuang YAN ; Zilin SUN ; Yadong SUN ; Liqin SUN ; Luying SUN ; Li YAN ; Yanbing LI ; Hong LI ; Shu LI ; Ling LI ; Yiming LI ; Chenzhong LI ; Hua YANG ; Jinkui YANG ; Ling YANG ; Ying YANG ; Tao YANG ; Xiao YANG ; Xinhua XIAO ; Dan WU ; Jinsong KUANG ; Lanjie HE ; Wei GU ; Jie SHEN ; Yongfeng SONG ; Qiao ZHANG ; Hong ZHANG ; Yuwei ZHANG ; Junqing ZHANG ; Xianfeng ZHANG ; Miao ZHANG ; Yifei ZHANG ; Yingli LU ; Hong CHEN ; Li CHEN ; Bing CHEN ; Shihong CHEN ; Guiyan CHEN ; Haibing CHEN ; Lei CHEN ; Yanyan CHEN ; Genben CHEN ; Yikun ZHOU ; Xianghai ZHOU ; Qiang ZHOU ; Jiaqiang ZHOU ; Hongting ZHENG ; Zhongyan SHAN ; Jiajun ZHAO ; Dong ZHAO ; Ji HU ; Jiang HU ; Xinguo HOU ; Bimin SHI ; Tianpei HONG ; Mingxia YUAN ; Weibo XIA ; Xuejiang GU ; Yong XU ; Shuguang PANG ; Tianshu GAO ; Zuhua GAO ; Xiaohui GUO ; Hongyi CAO ; Mingfeng CAO ; Xiaopei CAO ; Jing MA ; Bin LU ; Zhen LIANG ; Jun LIANG ; Min LONG ; Yongde PENG ; Jin LU ; Hongyun LU ; Yan LU ; Chunping ZENG ; Binhong WEN ; Xueyong LOU ; Qingbo GUAN ; Lin LIAO ; Xin LIAO ; Ping XIONG ; Yaoming XUE
Chinese Journal of Endocrinology and Metabolism 2025;41(11):891-907
Body weight abnormalities, including overweight, obesity, and underweight, have become a dual public health challenge in Chinese adults: overweight and obesity lead to a variety of chronic complications, while underweight increases the risks of malnutrition, sarcopenia, and organ dysfunction. To systematically address these issues, multidisciplinary experts in endocrinology, sports science, nutrition, and psychiatry from various regions have held multiple weight management seminars. Based on the latest epidemiological data and clinical evidence, they expanded the guideline to include assessment and intervention strategies for underweight, in addition to the core content of obesity management. This guideline outlines the etiological mechanisms, evaluation methods, and multidimensional management strategies for overweight and obesity, covering key areas such as diagnosis and assessment, medical nutrition therapy, exercise prescription, pharmacological intervention, and psychological support. It is intended to provide a scientific and standardized approach to weight management across the adult population, aiming to curb the rising prevalence of obesity, mitigate complications associated with abnormal body weight, and improve nutritional status and overall quality of life.
9.Analysis of factors influencing DRG payment system reform based on interpretive structural model
Tongbin XUE ; Ye WU ; Dian ZHOU ; Di TIAN ; Yuan ZHOU ; Yu ZHANG ; Manchen LYU ; Yuchen ZHANG ; Xiaohan JING ; Rui ZHOU
Chinese Journal of Hospital Administration 2025;41(3):210-215
Objective:To analyze the influencing factors of China′s DRG payment system reform(DRG reform) and its hierarchical relationship, for references for the in-depth promotion of China′s medical insurance payment reform.Methods:Relevant literature on DRG reform in China from databases such as CNKI, Wanfang Database, Pubmed, etc, were obtained. Content analysis method was used to extract the influencing factors of DRG reform. The correlation between each influencing factor was determined through expert discussion. An interpretive structural model(ISM) was constructed to analyze the hierarchical relationship of factors influencing DRG reform.Results:After analysis, the influencing factors(12) of DRG reform in China were included such as medical level, hospital management, and medical staff′s cognition and behavior. Among them, the local situation was the deep-level factor affecting DRG reform, 9 factors such as data quality assurance and policy design/implementation were the middle-level factors, and patients′ interests/needs and disease grouping were the surface-level factors.Conclusions:There were many influencing factors on the reform of China′s DRG payment system. It was suggested that relevant management departments in various regions should focus on the actual situation of the locality, take data quality and policy design and implementation as the key points of reform, formulate a scientific and reasonable DRG grouping scheme, safeguard the interests of patients, so as to promote the deepening of DRG reform.
10.Controllability Analysis of Structural Brain Networks in Young Smokers
Jing-Jing DING ; Fang DONG ; Hong-De WANG ; Kai YUAN ; Yong-Xin CHENG ; Juan WANG ; Yu-Xin MA ; Ting XUE ; Da-Hua YU
Progress in Biochemistry and Biophysics 2025;52(1):182-193
ObjectiveThe controllability changes of structural brain network were explored based on the control and brain network theory in young smokers, this may reveal that the controllability indicators can serve as a powerful factor to predict the sleep status in young smokers. MethodsFifty young smokers and 51 healthy controls from Inner Mongolia University of Science and Technology were enrolled. Diffusion tensor imaging (DTI) was used to construct structural brain network based on fractional anisotropy (FA) weight matrix. According to the control and brain network theory, the average controllability and the modal controllability were calculated. Two-sample t-test was used to compare the differences between the groups and Pearson correlation analysis to examine the correlation between significant average controllability and modal controllability with Fagerström Test of Nicotine Dependence (FTND) in young smokers. The nodes with the controllability score in the top 10% were selected as the super-controllers. Finally, we used BP neural network to predict the Pittsburgh Sleep Quality Index (PSQI) in young smokers. ResultsThe average controllability of dorsolateral superior frontal gyrus, supplementary motor area, lenticular nucleus putamen, and lenticular nucleus pallidum, and the modal controllability of orbital inferior frontal gyrus, supplementary motor area, gyrus rectus, and posterior cingulate gyrus in the young smokers’ group, were all significantly different from those of the healthy controls group (P<0.05). The average controllability of the right supplementary motor area (SMA.R) in the young smokers group was positively correlated with FTND (r=0.393 0, P=0.004 8), while modal controllability was negatively correlated with FTND (r=-0.330 1, P=0.019 2). ConclusionThe controllability of structural brain network in young smokers is abnormal. which may serve as an indicator to predict sleep condition. It may provide the imaging evidence for evaluating the cognitive function impairment in young smokers.

Result Analysis
Print
Save
E-mail